Overview of the Nervous System Breakdown 1 The

Overview of the Nervous System Breakdown 1. The Nervous system is divided into two parts the CNS (central nervous sys) and the PNS (peripheral nervous sys) 2. These two systems consists of the brain, spinal cord, and neurons

Central Nervous System CNS is composed of the brain and the spinal cord a. Responsible for integrating, processing, and coordinating sensory data and motor commands b. You stumble the CNS integrates info about balance and limb position and then recovers by sending motor commands where needed (without conscious effort) c. Also contains higher functions such as intelligence, memory, emotion and learning

Peripheral Nervous System 1. PNS: composed of two subdivisions of neurons that sends stimulus to the CNS and carries motor commands to peripheral tissues a. Afferent division brings sensory info from receptors b. Efferent division carries motor commands to muscles and glands (they are called effectors) i. Somatic nervous sys (SNS): voluntary contraction of skeletal muscles ii. Autonomic nervous sys (ANS): automatic movement and regulation of skeletal and smooth muscle due to stimulus (also known as a reflex)

Structure Of Neurons Cell Body (soma): contains the nucleus, most of the cytoplasm and cytoskeleton (cell can not divide due to lack of centrioles) Dendrites: variable number of slender processes that extend from the cell body, typically receives info from other neurons and sends toward cell body • Axon: long process from cell body that can propagate an electrical impulse (action potential) a. Axons can be covered in segments of Myelin (myelin is a wrapping of insulation that increases the speed of the action potential along the axon) b. Large areas of axon wrapped in myelin are called Internodes c. The small gaps between internodes are called Nodes or nodes of Ranvier

Synapse Interactions Synapse: site where one neuron communicates with another a. Presynaptic cell: cell that carries the message b. Postsynaptic cell: cell that receives message c. Neurotransmitters: chemicals released into the synapse by the presynaptic cell which affect the activity of the postsynaptic cell d. Neurotransmitters are released due to the number of action potentials, the more neurotransmitters that are released. BYGO 1 -10 Pg 453